DC Circuits Flashcards
A potential difference of 50 volts produces a current of 10 milliamperes through a resistance of?
5,000 ohms.
A conductor with a positive Q (charge) of 4C has 12.56 x 10^18 electrons added to it. It will have a Q =?
6.
The power dissipated by a load of known resistance connected across a known potential difference can be calculated by?
Working out the current flowing in the circuit by using Ohm’s law and multiplying the result by the resistance OR dividing the square of the potential difference by the value of the load resistance.
A current of 5A flows for 2 minutes. How many coulombs passed a point in the circuit?
600.
A circuit has a current flow of 6A. If the voltage is trebled, the new current will be?
18A.
A 10V battery supplies a resistive load of 10 ohms for 1 minute. What is the work done?
600J.
A galvanometer measures?
milliamps.
The voltage at point A is?
7 V.
A loss of electrical insulation results in?
a short circuit between the supply and earth.
A 3, 5 and 2 ohms resistance is connected in series with a 10 V battery. The voltage across the 2 ohms resistor is?
2 V.
What is the PD of a circuit which has a 40 mA current and a 1 kilohm resistance?
40 V.
Three branches in a circuit have currents entering of 3A, 4A and 5A. A fourth branch has 10 A leaving. A fifth branch must have?
2A leaving.
In a circuit containing three resistors of equal value connected in parallel, one resistor goes open circuit. The current in the other two resistors will?
remain the same.
20 amperes flow for 20 seconds. How many coulombs have flowed?
400.
If the resistance of an electrical circuit is increased?
the current will decrease.
If 2 coulombs flowed through a circuit in 2 seconds, the circuit would have?
1 amp.
If the voltage across a resistor is doubled?
the current is doubled.
The total current flowing in a circuit of 200 lamps in parallel, each of a resistance of 400 ohm and connected across an input of 100 volts is?
50 amps.
In the circuit shown the 24 volt battery has an internal resistance of 1 ohm and the ammeter indicates a current of 12 amperes. The value of the load resistance is?
1 ohm.
If service No. 1 is isolated from the supply busbar shown there will be?
a decrease in total current consumption.
If the cross-sectional area of a conductor is doubled, with voltage constant, the current will?
double.
If two resistors of 5 and 10 ohm respectively are connected in series and the current in the 5 ohm resistor is 1A. what is the current in the 10 ohm resistor?
1 amp.
The voltage in a series circuit?
is different in each component.
If voltage is 100V, resistance is 25 ohms, what is the current?
4 amperes.
A short circuit between the supply and earth?
could be very dangerous as the current drawn will be very high.
A circuit consists of 3 ohm, 5 ohm and 12 ohm resistors in series. The current flowing in the 5 ohm resistor is 10 amps. What is the applied voltage?
200 V.
Two resistors are connected in series and have an e.m.f. of V volts across them. If the voltages across the resistances are V1 and V2 then by Kirchhoff’s law?
V = V1 + V2.
A voltmeter is connected?
in parallel.
Since electrical supplies taken from a bus-bar are in parallel, isolating some of the services would?
reduce the current consumption from the bus-bar.
The current flowing through a circuit can be increased to four times its original value by?
doubling the applied voltage and halving the resistance.
In a circuit containing three resistors of equal value connected in series and one of the resistors short circuits, the effect is for the current in the other two resistors to?
increase.
In a series resistive circuit?
the total voltage is equal to the sum of the individual voltages.
The reading on the ammeter in the circuit shown is?
6A.
An ammeter is connected into a circuit in?
series.
What is the voltage at A?
26V.
What is the voltage at A?
26V
4 ohm resistor will drop 4/62ths of the 28V supply (i.e. 1.8V). So there will be approximately 26V left.
The source voltage in the circuit shown is?
200V
This is a standard potentiometer. It splits the voltage by the same ratio as the number of turns.
If the volts dropped across the 20 ohm resistor is 10 volts, the resistance of R1 is?
20 ohms
Find the current through the 20 ohm resistor (I = V/R = 10/20 = 0.5). The same current goes through all parts of a series circuit.
The current in the circuit shown is?
5 mA
Total R = 40 k ohms. I = V/R = 200/40,000 = 0.005A = 5mA.
What is the voltage across the 6 ohm resistor?
54V
V = I * R = 9 * 6 = 54V.
The unknown current in the network below is?
3A
Kirchhoff’s current law.
In a balanced Wheatstone bridge, across the centre of the bridge there is?
no current flow
The ammeter reads zero when it is balanced.
A 24V battery has an internal resistance of 1 ohm. The value of the load is?
1 ohm
Total R = V/I = 24/12 = 2 ohms. Subtract the internal resistance to get the external resistance.
In a parallel circuit with any number of 2 terminal connections?
the individual voltage drops is equal to the emf
Parallel circuit - the voltage drops across each branch is the source voltage.
What is the voltage across the series resistor in a 200V long shunt generator?
6V
V = I * R = 100 * 0.06 = 6V.
To find the internal resistance of a battery in a circuit of known current?
find the lost volts of the circuit
Find the difference between the Voltage On-load and the Voltage Off-load.
Find the voltage at point B.
10V
Total dropped by point B is 40/60 * 30 = 20V. Therefore, remaining voltage at B = 10V.
In a series circuit with 3 resistors, the current is?
even in all 3
The current is the same in all components in a series circuit.
What is the voltage dropped across resistor ‘A’?
20 V
28-(2 + 6) = 20 V.
What is the current through resistor C?
4.5A
It is 9A/2 (4.5A) only if C and D are the same.
Which is not thermally operated?
A limiting resistor
NIL.
In a Desynn indicator system, the rotor is?
a permanent magnet
NIL.
A load that is subject to a potential difference with a current running through it will?
dissipate power in the form of heat
NIL.
